


i can't resist your call

by glitterfox19



Category: Haikyuu!!
Genre: Alternate Universe, M/M, Magic, Sailing, Sirens, tsukki's a ship captain, yamaguchi is an adorable vegetarian siren
Language: English
Status: Completed
Published: 2020-12-23
Updated: 2020-12-23
Packaged: 2021-03-10 22:40:37
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,904
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28234824
Author URL: https://archiveofourown.org/users/glitterfox19/pseuds/glitterfox19
Summary: Male sirens died out a long time ago. The Encyclopedia of Magickal and Dangerous Kreechers says so. Somehow, Kei still manages to encounter one.
Relationships: Tsukishima Kei/Yamaguchi Tadashi
Comments: 5
Kudos: 71





	i can't resist your call

“Why can’t I deal with the sirens,” Bokuto complains, arms crossed across his chest. “I bet I could resist them.”

“Sure you could, Bo,” Kuroo says, grabbing a fistful of the other man’s tunic fabric to tug him forward. “I bet the sirens would fall in love with you and would forget to sing.”

“You think so!” he half-shouts, stars shining in his eyes. Kei wants to laugh so badly. He bites his lip and lets out a funny exhale from his nose. Kuroo shoots him a look, but it’s an understanding one, not a chastising one. “Tsukki gets all the cool jobs. It’s unfair.”

“Please stop calling me that,” Kei says. “And I’m dealing with the sirens because I’m the only one of the crew who isn’t about to fall for a random woman.”

“Hey. I would never.”

“Kuroo, you pick up someone new every time we dock. Shut up.”

“Okay, captain!” Kuroo says with a mock-salute. Kei scowls. “We’ll be down here trying very hard to ignore the very sexy fish lady that will be outside. Have fun ruining some mythical creatures’ mid-day meal, or whatever.”

“You’re the weirdest man I think I’ve ever met,” Kei mutters as the door to the cabin swings shut behind him. He takes a deep breath and stretches his arms as far up as they can go.

Any minute now, the Lady Karasuno would be approaching the Ko islands, composed of dense vegetation and jagged cliffs. There was a siren coven nestled in the middle of a formerly well-used trading route. It had lost its popularity after confirmed sightings, but every traveller who’d gone through since noted that they had no trouble. Kei knows that time is of the essence with this cargo shipment and he figures it would be safe enough with the sirens. He’s lucky he doesn’t need to tie himself to the mast to prevent himself from losing it. After all, everyone knows that all sirens are women.

Kei leans against the front of the ship. The channel is approaching; the ship will soon be bracketed with high, rocky cliff walls. If the sirens are going to make their move, now is the best time.

There’s a flash in the corner of his eye. He turns his gaze to see what the disturbance was, and sees a siren waving at him from a slightly-submerged rock perch a few meters away from the cliffs. Kei cocks his head. The siren’s hair is shorter than how the encyclopedia showed traditional locks; it frames the creature’s chin rather than the shoulders. And it’s remarkably flat-chested…

“Hi!” it chirps. That is not a woman’s voice. “Are you the captain?”

“Male sirens don’t exist,” Kei says flatly instead of responding to the question. “They died out.”

The siren looks briefly puzzled. “Well, um, I exist.” He flicks his tail. The sun catches his scales, and for a moment, Kei is dazzled. They’re a beautiful shade of green, like seagrass or a turtle’s dappled shell. Kei frowns and looks away. He refuses to give in. “What made you think all sirens were female?”

“That’s what every authority on the subject says.”

“I think I’m a good authority on the subject of sirens. And I say we exist.”

“Yeah, I can see that.” Kei feels his jaw begin to tense up. None of the crew is resistant to a man’s charms. Even if this colony of sirens is friendly, he isn’t keen on testing out that theory. They need to get through the channel as fast as possible before someone becomes a snack.

“You look worried. I promise I’m not going to eat you!” 

“I wasn’t born yesterday, fishbrain,” Kei spits. The siren wilts against his rock, his tail dropping back beneath the water. Kei tries not to think about the dancing colors that linger behind his eyelids. “I’m not going to fall for your spell.”

The siren pouts. “I’m not lying! And I bet you will fall for my spell if I were to cast it.”

“I bet I won’t,” Kei responds. _Why am I falling for these childish taunts so easily? What's gotten into me?_

“How about a bet?”

“A bet?”

“If you win, I’ll let you pass. If I win…” The siren drops his chin into his palm and glances up at the sky before meeting Kei’s eyes with a cheery grin. It would probably be cheerier if he had human teeth, Kei supposes, but the smile is still effortlessly charming. Kei shakes his head to clear his muddled thoughts. _Stay logical. Stay focused._ “I’ll probably still let you pass. But you have to come back here and give me human trinkets.”

“Human trinkets?” Kei scoffs. _Why doesn’t he want to eat me? This must be a trap._

____

____

“Yeah! Humans are such silly creatures, y’see. And they’re so interesting! So if I win, you have to visit me once a week and entertain me.”

“Entertain you? I thought humans were your prey. You're not supposed to play with your food.”

The siren stares at him, eyes nearly popping out of his head, jaw slack. Kei hopes he didn't accidentally say something exceptionally offensive in siren culture. He says a quick goodbye to his loved ones and hopes that the gods will take pity on him. "I would never eat a human. My colony only eats fish."

Now it's Kei's turn to be surprised. "I've never heard of a siren that doesn't snack on people."

"Gross. You probably taste like dirt or something. Creatures that live in the ocean taste clean." Kei wonders if he should take offense to that, but the siren is so obviously distracted by the apparently horrifying idea of eating humans that he keeps his mouth shut.

"Back to our bet. What do you do in your spare time, Tsukki?” Kei takes a step back and the siren tuts under his breath. “You’re supposed to be getting closer to me. I’m a miserable excuse of a siren.”

“How do you know that name?”

The siren blinks at him. “I heard the other sailors say it when they were talking to you.” 

“You’ve been watching me?” _Why does that thought send a thrill up my spine?_

The siren slides down his rock, his shoulders disappearing under the waves. The tip of his tail pokes out, waving quickly back and forth. He won’t meet Kei’s eyes. “Uh, yeah? Sirens have good hearing. And it’s good to…” The siren clears his throat and surges back up from the water. Kei forces himself not to stare at the way water rushes down the siren’s shoulders and bare chest. “You didn’t answer my question. What do you do when you’re not sailing?”

“I read books.”

The siren’s eyes are wide, all previous nervousness forgotten. “What’s a books?”

“A book,” Kei corrects, and he starts to smirk without even meaning to. He thinks for a moment, trying to decide how to describe something so elementary to someone with minimal understanding of... well, anything. “A book is when someone takes spoken language and keeps physical copies of it to pass down for future generations.”

“How do they do that?”

“By using symbols that correspond to spoken language. You don’t need to hear a story out loud anymore, you can just look.” Kei’s not sure if the siren’s aware of his own movement. He’s risen almost entirely out of the water, his full attention clearly on Kei. He’s leaning as far forward as he can without falling forward. “It allows us to learn about places we’ll never visit, or about creatures foreign to our lands, or to have access to stories about people who don’t exist.”

“That’s so cool!” The siren’s eyes sparkle like the waves lapping at his rock. He wiggles slightly. “Now I want to win even more.”

“I won’t make it easy for you.”

The siren grins, his fangs poking out from under his lips. “I’m glad you’re rising to the challenge, Tsukki.”

“Kei.” _Why did I say that? The siren hasn’t even started to work his magic. Why do I feel like I’m under his thrall already?_

“Eh?”

“Tsukishima Kei. That’s my full name.” He feels his cheeks begin to pink and thanks every god out there that Kuroo and Bokuto are below deck where his words can’t be overheard. They’d be mocking him for talking so seriously with something so dangerous. Someone so dangerous. 

“Names are powerful things, you know,” the siren says, but he looks confused, not cunning. “Not that I can do anything with them.”

“I know you can’t. I read about what sirens are like in books.”

“My name is Lucky Claw Catches Most Fish. Um, you can call me Tadashi.”

“Okay then, Tadashi,” Kei says. “Do your worst.”

Tadashi dips under the water for a moment before emerging once more. His wet hair dangles in front of his face, dripping ocean water onto his face, a stubborn piece somehow sticking up straight in the air. A droplet hangs off of his parted lips. His hands are splayed against the rock, the webbing between them stretched thin. He looks almost human.

He starts to hum at first. Kei sucks in a deep breath and closes his eyes. _Focus. Focus. Focus._ The melody is something he’s never heard before, but his flesh erupts in goosebumps regardless. It feels nostalgic, like when his mother would stroke his forehead when he had a fever.

When he wrenches his eyes open, he sees Tadashi staring at him from under his eyelashes. The sun has broken through a cloud, illuminating the siren’s face with gold. Kei can now see the splattering of freckles across Tadashi’s face, the flecks of green that match his scales in his eyes. Kei almost takes a step forward before he forces himself to shut his eyes again.

Then Tadashi begins to sing.

The words are not in a human language, but somehow, Kei can understand. The siren sings of young love, of being at home in someone else’s arms, of pride in your loved ones and of loving and being loved in return. Kei feels tears start to fall from his closed eyes. _What if I give up? It doesn’t matter, it’s not like he’s going to eat me. This isn’t important._

“Tsukki,” Tadashi says, a note of warning in his voice. Kei opens his eyes and sees the siren has an eyebrow raised. “You’re not going to give up that easily, are you?” 

Kei looks away. “It’s not like my life is at stake.”

“Don’t you want to be able to say that you’re more powerful than a siren?”

For a moment, the only sound is the waves lapping against the rock and the creaking of the ship. Kei curls his toes, reminding his feet to stay rooted to the deck. “I’m not giving up. Keep singing.”

Tadashi grins. It’s somehow brighter than the light reflecting off the water. He starts up his lilting melody again, and now Kei can watch as the magic floats from the siren’s mouth and spirals towards him. Tadashi’s magic is sea-green and wiggly, almost like it wants to escape in every direction. It settles on Kei’s skin like a gentle caress and he shivers.

The song beats its rhythm into his heart. It asks him if he’s ever been loved before. It knows he wants to be loved, cherished, praised. Don’t you want to be happy, Tsukishima Kei? Take a step forward. Take a step forward and you’ll be loved for ever and ever and ever. Tadashi will love you. He’ll hold you close and stroke your back and show him a world you’ve always wondered about. What’s life like underneath the waves of the ocean? He’ll show you. He’ll adore you. You’ll never feel sorrow again. Your every need will be met. Come on now. It’s just a step.

Kei’s not sure how long he endures the song. He’s curled up in a ball now, his hands over his ears, forehead against the cool, ocean-sprayed wood of the ship’s deck. It didn’t deafen the intensity, but it reminded him of what he’s trying to do.

Tsukki, Tadashi says, his song humming its tune deep in his bones, I’ll do anything for you.

Tadashi stops singing. Kei blinks, disoriented, and realizes he’s managed to rise to his feet and take a step forward, hand outstretched towards the siren. He crumples to the ground again, his breaths escaping him in quick gasps. The magic leaves him feeling clammy and shaken.

When he manages to raise his head again, the siren is peeking over the front of the ship, eyes wide, tail dangling underneath him. He must have incredible upper body strength to manage to hold himself up like that. “A-are you okay? No one’s ever lasted that long against me.”

“I’m fine,” he forces out, struggling to his knees. Kei offers him a weak smile. Tadashi returns it shakily. “You’re very alluring.”

“I think that means it’s a tie,” Tadashi muses. “What does that mean?”

“It means I’ll visit you every week.” The siren’s mouth falls open, revealing even more razor-sharp teeth. “In return, I want you to sing for me when I visit. Real songs, not the kind meant to lure me to my death.”

“I-I told you, I don't eat people. I don't even think I could have such strong magic like that, anyway.” The siren’s face is bright red.

“Have more faith in yourself, Tadashi.” Kei moves to the front of the ship and lays flat on his stomach so that he’s eye-to-eye with the siren. “I like your songs.”

“I like you,” Tadashi says, and then moves to clap his hands over his mouth. Except he’s forgotten that was keeping him attached to the side of the ship, so he falls into the water below, flailing inelegantly. Kei covers his snickers with a hand. 

“What trinket do you want first, Tadashi?” Kei calls. The siren emerges from the waves, shoulders scrunched up to his ears.

“A books,” he says. “Your favorite one.”

“A book would get destroyed by the water. I can read it to you, though.”

“Okay. Promise me.”

“I promise,” Kei says, and then holds out a hand. Tadashi eyes it warily. “Humans show that they intend to keep promises by shaking hands.” 

“I don’t want to humiliate myself and fall again.”

“I believe in you, Tadashi.” Tadashi flushes again before clambering up the side of the ship. He wraps his tail around the front of the ship extra-tight before offering his hand to Kei. Kei grabs it firmly. It’s cool and slippery in his grip. The siren’s fingers are almost as long as his own. Kei is struck by how little he wants to let go, but he releases his grip eventually.

“Sirens seal a promise with a kiss,” Tadashi blurts, face impossibly red. “Since we’re exchanging bits of our cultures, now.”

“Do they really?” Kei moves closer. Tadashi tightens his grip on the side of the ship. “I guess it’s only fair.”

“Y-yeah, only fair. Um, should I climb over? To make it easier?”

“Sure.” Kei watches as Tadashi struggles to make it over the bow, but he manages to swing his tail over the side. It flops rather uselessly against the wood. “Is there magic that could make you look human?”

“There’s an ocean witch near my colony who says she can do it, but I’m not sure I trust her,” Tadashi says, pulling a face. _Cute,_ Kei thinks. That's quickly followed up with _I’m fucked, aren’t I_. “But maybe someone else would be willing. Why?”

“Just wondering,” Kei says, moving closer. “Don’t we have a promise to seal?”

Tadashi bobs his head. “Y-yes.” He presses his forehead against Kei’s, eyes impossibly wide. “Uh. Okay. Promise time.”

Kei puts a hand on Tadashi’s cheek. “I promise I’ll bring my favorite book to you, Tadashi.” He closes his eyes and presses their lips together. Tadashi tastes of salt and cream and the moment when he was first appointed captain of the Lady Karasuno. He sinks into the siren, raising his other hand reaching up to curl around the siren's shoulder. Tadashi’s lips are a spell of their own.

When they separate, Tadashi keeps his eyes closed for a beat longer before blinking them open, eyelashes fluttering. Kei flexes his fingers to prevent himself from reaching out and pulling him in again. “Um. That was good! Our promise is definitely safe now.”

“Tadashi, I know sirens only kiss as a part of a courting ritual.”

“What!” The siren squeaks and sits up, waving his hands from side to side. “You must’ve heard the wrong thing! Books can’t be all-powerful, can they? Where would you have even heard that? We sirens are very mysterious, y’know!” 

“How about you tell me about mates when I see you next time? I can tell you about human mates, too. My favorite book talks about those a lot.”

“I’ll be at your port at midnight,” Tadashi says, tail thumping against the wood. “As long as you tell me where that is. I don't mind swimming even if it's far away.”

“Perfect.”

Tadashi twists about awkwardly, a shy blush spreading across his chest and his face. “Um. You might need to throw me back in the water. I don’t think I can get around your ship with this tail.”

Kei can’t stop himself from laughing out loud.

**Author's Note:**

> random ursula reference lol. thanks 4 reading!


End file.
